Table 2.

Evaluation of Conditions for a One-Pot Conversion of Trisilyl Inosine 3 to the O⁶-Methyl Ether 2

entry	conditionsa	timeb	% yieldc
1	DBU (4 molar equiv), BOP (2 molar equiv), MeOH (20 molar equiv), THF, rt	24 h	--d
2	DBU (4 molar equiv), BOP (2 molar equiv), THF, rt Then evaporate solvent and add MeOH (20 molar equiv), rt	step 1: 2 h step 2: 24 h	--e
3	DBU (2 molar equiv), BOP (2 molar equiv), THF, rt Then add DBU (2 molar equiv) and MeOH (20 molar equiv), rt	step1: 2 h step 2: 8 h	74
4	DBU (2 molar equiv), BOP (2 molar equiv), THF, rt Then evaporate solvent and add DBU (2 molar equiv) and MeOH (20 molar equiv), rt	step 1: 2 h step 2: 4 h	76
5	Cs2CO3 (4 molar equiv), BOP (2 molar equiv), MeOH (20 molar equiv), THF, rt	48 h	--d
6	Cs2CO3 (4 molar equiv), BOP (2 molar equiv), THF, rt Then add MeOH (20 molar equiv), rt	step 1: 20 min step 2: 24 h	--e
7	DBU (2 molar equiv), BOP (2 molar equiv), THF, rt Then evaporate solvent and add Cs2CO3 (2 molar equiv) and MeOH (20 molar equiv), rt	step 1: 2 h step 2: 1 h	77
8	Cs2CO3 (2 molar equiv), BOP (2 molar equiv), THF, rt Then add Cs2CO3 (2 molar equiv) and MeOH (20 molar equiv), rt	step 1: 10 min step 2: 2 h	94
9	Cs2CO3 (2 molar equiv), BOP (2 molar equiv), THF, rt Then evaporate solvent and add Cs2CO3 (2 molar equiv) and MeOH (20 molar equiv), rt	step 1: 10 min step 2: 10 min	94

^aReactions were conducted using 0.16 mmol of 3 in THF (2 mL).

^bReactions were monitored by TLC.

^cYields reported are of isolated and purified product.

^dMixture of products.

^eFormation of the O⁶-(benzotriazol-1-yl) derivative 1 was complete as observed by TLC.